Andromeda's VariFocus Plug-in

Controlling depth of field has, traditionally, been a camera technique. Stopping
down the lens provides more depth of field and opening up the lens less. Isolating
focus to a narrow plane of a scene can have a dramatic effect. And it's a popular
enough one to have a name: selective focus.

But digital photography is a funny thing. Some things, like double exposure,
that have been camera techniques, become image editing tricks. And others, like
selective focus, can be either.

But there is a very fine line any image editor must learn to observe. It's
the line beyond which believability dissolves. Image editors make it very easy
to composite images, moving a gorilla shot at the local zoo to your living room
couch, say. But it isn't believable (generally speaking) because you are mixing
outdoor light and indoor with completely different shadow effects to boot.

So when we say you can do selective focus in your image editor, we aren't
talking about your everyday Guassian blur. We're talking about using a sophisticated
Photoshop-compatible plug-in like Andromeda's VariFocus. This tool applies a
believable gradient to a focus mask. A demo is available at http://www.andromeda.com.

KEEP IT SIMPLE, SPORT

But let's start simple.

We have a number of images of the nationally-ranked Pasini Academy football
team (no relation). One of our favorites is taken from the sidelines as the
Pasini Eagles, on defense, threaten to thwart the plans of the El Cajon Braves.
Nothing is actually happening at the moment the shutter is snapped. Which is
the whole point of defense.

What the high school year book art director would like us to do (hey, it always
helps to imagine yourself employed) is to keep the one unobscured P on a lineman's
helmet in focus and gradually blur the rest of offense and defense. This, he
tells us, indicates our man is thinking. Not speculating, not day dreaming,
but thinking.

Piece of cake (well, with this filter, anyway).

The VariFocus Interface(Click for the 107K full-size screen shot)

Open the image in your image editor and select the VariFocus filter from the
Andromeda option in the Filters menu. You have a moveable dialog box with a
preview of your image on the left and Andromeda's (less-than-intuitive) icons
for About/Cancel/OK buttons. That much is (fairly) clear.

About, Cancel and OK

The About button, by the way, sports a Preferences button. Its No Change and
OK buttons let you set the filter's Photoshop support level.

Below the preview is a Help pane which reveals in plain English what the (odd
looking) icons actually do whenever you roll your mouse over them. There are
a lot of them, so this isn't just handy, it's a lifesaver.

The (Indispensable) Help Pane

On the right side of the dialog box is where we'll actually be working.

The Work Pad

Focus Masks

The upper pane contains a representation of the active mask. What, in gray,
the blurring will look like. Below that is a group of 16 possible masks. All
sorts of shapes. For our job, we need Number 3. It's a small dark circle that
grays gradually out to a white background. Just the ticket.

So we click on it to make it active.

This is where the work starts. The first problem is to align the center of
the mask to the helmet with the visible P in the image. VariFocus makes this
easy. You can either click in the preview or the active mask pane to position
the center of the mask. A small progress bar pops up on the preview while it
is being redrawn.

Once the mask is aligned, we have to adjust the rate at which the image blurs.
We want to be able to tell, for example, that beyond the helmet there is a body
and beyond that a team. But we don't want to be able to recognize any of the
truants. Might not graduate.

This refinement isn't too laborious either. But a bit tricky. We can change
the size of the mask with a little slider just under the active mask pane. That's
probably all we have to do. But we can also change the degree of defocusing
with another slide just under the preview. These are not quite the same thing.
But working first with the scale and then with the degree we can precisely control
the effect.

Don't blink, we're done!

VARIATIONS ON A THEME

There are 19 user interface elements in the dialog box. We didn't need them
all for this project.

We defocused but we might have sharpened instead by clicking on the Sharpen
button (which unclicks the Defocus button). Another example of the non-intuitive
interface design.

The Defocus/Sharpen Buttons

We might also not have moved the center of the mask to the center of
the helmet by clicking on either the preview or the active mask. We might, instead,
have stretched the mask in the direction we were dragging, turning our
circular mask into an ellipse.

Orientations

We could also have reversed, flipped (along either the horizontal or vertical
axis) or rotated the mask. With our circular mask these options weren't particularly
tempting, but it's nice to know they'll be there when we need them.

Finally a bar icon at the top right lets us move the whole dialog box around.

The Bar

THE KEY TO THE THING

The trick to getting the effect you want is having the right mask. Our simple
example, spotlighting a helmet, used a circular mask. The other 15 options are
various graduated patterns ranging from linear wipes to radial blurs (including
an option to apply the effect uniformly). You can exclude any part of your original
image from their powers simply by selecting it (usually using the lasso) and
inversing the selection. VariFocus will tamper only with the selection.

Chapter Three of the PDF manual gives several real world examples of the filter
in use. Defocusing with a selection or a mask and creating a glow and a halo
illustrate the use of the Defocus/Sharpen modes and their Amount/Radius sliders.

It even shows how to build your own blur/sharpen masks (you can see ours in
the first pane of the focus masks illustration above). Which is nice to have
but not something you'll often need.

Our Man Thinking(Click for 46K full-size original)

But the beauty of VariFocus is having at your disposal a variable blur mask.
The blur (or sharpen) can be applied in a number of graduated patterns. Focus
is the obvious application, but we couldn't help but wonder why not apply any
other filter (besides blur/sharpen) to the variable mask engine in this filter.

CONCLUSION

Thumbs down on the interface. Clearly labeled buttons would be a big improvement
(imagine what the world would be like if every filter had a unique user
interface). We liked the separate (rather than stacked, like layers) preview
and active mask planes, but the progress bar should draw itself somewhere else
rather than on top of the preview. It's annoying there.

But those are quibbles. VariFocus does indeed provide an easy-to-use graduated
blur with a comprehensive set of masks. And it's fun, too!